Composite material for a passive variable radiator

Abstract

A composite material includes a polymer matrix and a quantity of electrically conductive microparticles dispersed within the polymer matrix in an amount and distribution structured so that the composite material exhibits an increase in thermal emissivity of at least about 8% with increasing temperature of the composite material, for temperatures over a range of 23° C.-60° C. inclusive. The composite material may be used as (or as part of) a passive variable radiator for cooling an object in thermal communication with the composite material.

1 . A composite material comprising:
 a polymer matrix; and   a quantity of electrically conductive microparticles dispersed within the polymer matrix in an amount and distribution structured so that the composite material exhibits an increase in thermal emissivity of at least about 8% with increasing temperature of the composite material, for temperatures over a range of 23° C.-60° C. inclusive.   
     
     
         2 . The composite material of  claim 1  wherein the microparticles comprise flaky-shaped microparticles. 
     
     
         3 . The composite material of  claim 2  wherein the flaky-shaped microparticles are dispersed within the polymer matrix in an amount of 30%±1% by volume. 
     
     
         4 . The composite material of  claim 1  wherein the microparticles comprise spiky-shaped microparticles. 
     
     
         5 . The composite material of  claim 4  wherein the spiky-shaped microparticles are dispersed within the polymer matrix in an amount of 30%±1% by volume. 
     
     
         6 . The composite material of  claim 1  wherein a polymer forming the matrix has a thermal emissivity of at least 0.90 for when the polymer is at a temperature within a range of 23° C.-60° C. inclusive. 
     
     
         7 . The composite material of  claim 1  wherein the polymer matrix comprises a polydimethylsiloxane (PDMS) resin. 
     
     
         8 . The composite material of  claim 1  wherein the microparticles comprise nickel microparticles. 
     
     
         9 . The composite material of  claim 1  wherein the quantity of electrically conductive microparticles is dispersed within the polymer matrix in an amount and distribution structured so that the composite material exhibits an increase in thermal emissivity of at least about 20% with increasing temperature of the composite material, for temperatures in the range of 23° C.-60° C. inclusive. 
     
     
         10 . The composite material of  claim 1  wherein a thickness of the material is 0.004±0.0004 inch. 
     
     
         11 . A composite material comprising:
 a polymer matrix having a thermal emissivity of at least 0.90 over a temperature range of 23° C.-60° C. inclusive; and   a quantity of electrically conductive flaky microparticles dispersed within the polymer matrix in an amount of 30%±1 by volume.   
     
     
         12 . The composite material of  claim 11  wherein a thickness of the material is 0.004±0.0004 inch. 
     
     
         13 . (canceled) 
     
     
         14 . (canceled)